T he most recent meta-analysis 1 of 37 randomized trials of off-pump coronary artery bypass (OPCAB) versus conventional coronary artery bypass grafting (CABG) demonstrated that mortality, stroke, myocardial infarction, and renal failure were not reduced in OPCAB; however, selected short-term and midterm clinical and resource outcomes were improved compared with CABG. The previous cumulative analysis (by Parolari and associates 2 ) of 5 prospective randomized studies (by Nathoe, 3 Khan, 4 Puskas, 5 Widimsky, 6 Lingaas, 7 and their associates) then available in the literature, however, documented a reduction in postoperative patency of bypass grafts performed during OPCAB procedures. Since the meta-analysis by Parolari and associates 2 was conducted, Lingaas and colleagues 8 have updated the 3-month patency, 7 and Kobayashi and coworkers 9 and Al-Ruzzeh and associates 10 have reported results of other randomized controlled trials. In these trials, 8-10 OPCAB provided the same angiographic graft patency as CABG, despite the conclusion of the meta-analysis by Parolari and colleagues. 2 To reassess differences in graft patency between OPCAB and CABG, we performed a meta-analysis of currently available randomized controlled trials of OPCAB versus CABG.
DiscussionThe present meta-analysis demonstrated a significant increase in overall graft "occlusion," especially in venous graft "occlusion," with OPCAB relative to CABG. On the one hand, OPCAB de-From the
ccording to a meta-analysis by Cheng and associates 1 of 21 randomized clinical trials (RCTs) of off-pump versus on-pump coronary artery bypass grafting (CABG), postoperative 30-day stroke was not statistically significantly reduced (odds ratio, 0.68; 95% confidence interval [CI], 0.33-1.40) in the off-pump group. In the most recent meta-analysis by Sedrakyan and colleagues 2 of 16 RCTs, however, off-pump use was associated with 50% relative risk (RR) reduction of stroke (RR, 0.50; 95% CI, 0.27-0.93) as compared with that with on-pump CABG. To determine whether off-pump surgery is associated with reduced occurrence of stroke as compared with that of on-pump CABG, we performed a meta-analysis of currently available RCTs of off-pump versus on-pump CABG and discussed the discordant results found in the published literature.
In a review article by Mastracci and Cinà, 1 they stated that the pooled estimate of the effect of screening on abdominal aortic aneurysm (AAA)-related mortality showed a relative risk of 0.60 (95% confidence interval [CI], 0.45 to 0.80) in favor of screening men Ͼ65 years of age. The review included four reports of randomized controlled trials (RCTs): the Viborg Country study (mean 4.3-year follow-up), 2 the Western Australia study (median 3.6-year follow-up), 3 the Chichester study (men) (mean 10-year follow-up), 4 and the Multicentre Aneurysm Screening Study (MASS) (mean 4.1-year follow-up). 5 Longer follow-up results of several RCTs, however, have been published to date. Although a systematic review by Fleming et al 6 and our meta-analyses 7,8 demonstrated no benefit of screening for all-cause mortality, Mastracci and Cinà 1 did not state all-cause mortality. Therefore, we performed a meta-analysis of currently available longest follow-up results (both AAA-related and all-cause mortality) of RCTs of screening for AAA in men.Our comprehensive search identified four reports (Table): the Viborg Country study (median 9.6-year follow-up), 9 the Western Australia study (median 3.6-year follow-up), 3 the Chichester study (men) (over 15-year follow-up), 10 and the MASS (mean 7.1-year follow-up). 11 Two of the four individual reports demonstrated a statistically significant benefit of screening over control for AAArelated mortality. Pooled analysis of the four reports demonstrated a statistically significant reduction in AAA-related mortality with screening relative to control in a random-effect model (risk difference [RD], Ϫ0.25%; 95% CI, Ϫ0.46% to Ϫ0.04%). Two of the four individual reports demonstrated a statistically significant benefit of screening over control for all-cause mortality. Pooled analysis of the four reports demonstrated a statistically significant reduction in allcause mortality with screening relative to control in a random-effect model (RD, Ϫ1.06%, 95% CI Ϫ1.81% to Ϫ0.31%).In conclusion, the present meta-analysis demonstrated that screening for AAA significantly reduced not only AAA-related but also all-cause mortality in men Ͼ65 years of age.
The randomized controlled trial (RCT) by Kedora et al 1 showed that management of femoropopliteal (FP) arterial occlusive disease using percutaneous treatment with an expanded polytetrafluoroethylene (PTFE)/nitinol self-expanding stent graft was comparable to surgical revascularization with conventional above knee (AK)-FP bypass using synthetic material up to 12 months. In the surgical bypass group, Dacron grafts were used in 64%, and expanded PTFE was used in 36%. We would like to suggest, however, that saphenous vein (SV) grafts should be used instead of synthetic material as conduit of the FP bypass in the control group because of the following reasons. According to the meta-analysis of uncontrolled series by Pereira et al, 2 SV grafts performed better than PTFE grafts in AK-FP bypass. When only RCTs in the systematic review of AK-FP bypass by Klinkert et al 3 were considered, the patency of SV grafts was better than for PTFE grafts. The most recent meta-analysis by us 4 of currently available five RCTs also demonstrated that SV grafts were superior to PTFE grafts in AK-FP bypass: the pooled primary graft patency of SV and PTFE grafts were 86.6% and 83.7% (P ϭ .3957) at 1 year, 82.6% and 74.6% (P ϭ .0198) at 2 years, 79.2% and 65.3% (P ϭ .0011) at 3 years, 77.6% and 61.3% (P Ͻ .0001) at 4 years, and 76.4% and 56.1% (P Ͻ .0001) at 5 years, respectively. Because the type of prosthetic (Dacron or PTFE) used for AK-FP bypass, grafts did not affect 5-year patency rates in the RCT by Green et al, 5 SV grafts probably surpass both Dacron and PTFE grafts in patency of AK-FP bypass. Therefore, to compare the efficacy of the stent graft vs open surgical AK-FP bypass, conduit of the bypass would be SV rather than Dacron or PTFE. If a stent graft is not superior to, but comparable to AK-FP bypass using synthetic material, it might be inferior to the bypass using SV grafts.
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